| 摘要 |
<p>PURPOSE:To prevent the failure in the commutation of a chopper circuit due to the temporary decrease in the voltage of a battery and the operation of a commutation failure protecting circuit by interrupting a chopper circuit only for the prescribed period of time when the voltage of a battery becomes lower than a reference voltage due to the start of other DC motor. CONSTITUTION:A chopper circuit 6 is controlled by a signal responsive to the operated amount of an accelerator outputted from an oscillator 15. When the circuit 6 fails in its commutation, the voltage of a terminal L abruptly decreases, a commutation failure protecting circuit 13 operates, thereby interrupting a transistor 12. In this manner, the energizations of drive coils 8, 9 of contactors 4, 5 are released, and a drive DC motor 2 is stopped. When the start switch 20 of a loading DC motor 17 is closed so that the voltage of the battery 1 becomes lower than the reference voltage, a signal is outputted from an AND circuit 21, and the circuit 15 interrupts the circuit 16 only for the prescribed period of time.</p> |
